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Arabinosyl Transferase
An arabinosyltransferase is a transferase enzyme acting upon arabinose. This enzyme is involved in polymerisation of arabinogalactan (an essential component of the mycobacterial cell wall). Mycobacterially, the more precise term is arabinofuranosyltransferase, since the arabinose residues occur only in a furanose form. This enzyme has important clinical applications as it is believed to be the target of the antimycobacterial drug ethambutol. References {{InterPro content, IPR007680 Protein families Transferases ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabinose
Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group. For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.The D/L nomenclature does not refer to the molecule's optical rotation properties but to its structural analogy to glyceraldehyde. However, L-arabinose is in fact more common than D-arabinose in nature and is found in nature as a component of biopolymers such as hemicellulose and pectin. The L-arabinose operon, also known as the araBAD operon, has been the subject of much biomolecular research. The operon directs the catabolism of arabinose in ''E. coli'', and it is dynamically activated in the presence of arabinose and the absence of glucose. A classic method for the organic synthesis of arabinose from glucose is the Wohl degradation. : Etymology Arabinose gets its name from gum arabic, from which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transferase
A transferase is any one of a class of enzymes that catalyse the transfer of specific functional groups (e.g. a methyl or glycosyl group) from one molecule (called the donor) to another (called the acceptor). They are involved in hundreds of different biochemical pathways throughout biology, and are integral to some of life's most important processes. Transferases are involved in myriad reactions in the cell. Three examples of these reactions are the activity of coenzyme A (CoA) transferase, which transfers thiol esters, the action of N-acetyltransferase, which is part of the pathway that metabolizes tryptophan, and the regulation of pyruvate dehydrogenase (PDH), which converts pyruvate to acetyl CoA. Transferases are also utilized during translation. In this case, an amino acid chain is the functional group transferred by a peptidyl transferase. The transfer involves the removal of the growing amino acid chain from the tRNA molecule in the A-site of the ribosome and its subse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabinose
Arabinose is an aldopentose – a monosaccharide containing five carbon atoms, and including an aldehyde (CHO) functional group. For biosynthetic reasons, most saccharides are almost always more abundant in nature as the "D"-form, or structurally analogous to D-glyceraldehyde.The D/L nomenclature does not refer to the molecule's optical rotation properties but to its structural analogy to glyceraldehyde. However, L-arabinose is in fact more common than D-arabinose in nature and is found in nature as a component of biopolymers such as hemicellulose and pectin. The L-arabinose operon, also known as the araBAD operon, has been the subject of much biomolecular research. The operon directs the catabolism of arabinose in ''E. coli'', and it is dynamically activated in the presence of arabinose and the absence of glucose. A classic method for the organic synthesis of arabinose from glucose is the Wohl degradation. : Etymology Arabinose gets its name from gum arabic, from which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabinogalactan
Arabinogalactan, also known as galactoarabinan, larch arabinogalactan, and larch gum, is a biopolymer consisting of arabinose and galactose monosaccharides. Two classes of arabinogalactans are found in nature: plant arabinogalactan and microbial arabinogalactan. In plants, it is a major component of many gums, including gum arabic and gum ghatti. It is often found attached to proteins, and the resulting arabinogalactan protein (AGP) functions as both an intercellular signaling molecule and a glue to seal plant wounds. The microbial arabinogalactan is a major structural component of the mycobacterial cell wall. Both the arabinose and galactose exist solely in the furanose configuration. The galactan portion of microbial arabinogalactan is linear, consisting of approximately 30 units with alternating β-(1-5) and β-(1-6) glycosidic linkages. The arabinan chain, which consists of about 30 residues, is attached at three branch points within the galactan chain, believed to be at re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mycobacterial
''Mycobacterium'' is a genus of over 190 species in the phylum Actinomycetota, assigned its own family, Mycobacteriaceae. This genus includes pathogens known to cause serious diseases in mammals, including tuberculosis ('' M. tuberculosis'') and leprosy ('' M. leprae'') in humans. The Greek prefix ''myco-'' means 'fungus', alluding to this genus' mold-like colony surfaces. Since this genus has cell walls with Gram-positive and Gram-negative features, acid-fast staining is used to emphasize their resistance to acids, compared to other cell types. Metabolism and Morphology Mycobacteria are aerobic with 0.2-0.6 µm wide and 1.0-10 µm long rod shapes. They are generally non-motile, except for the species ''Mycobacterium marinum'', which has been shown to be motile within macrophages. Mycobacteria possess capsules and most do not form endospores. ''M. marinum'' and perhaps ''M. bovis'' have been shown to sporulate; however, this has been contested by further research. The disti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ethambutol
Ethambutol (EMB, E) is a medication primarily used to treat tuberculosis. It is usually given in combination with other tuberculosis medications, such as isoniazid, rifampicin and pyrazinamide. It may also be used to treat ''Mycobacterium avium'' complex, and ''Mycobacterium kansasii''. It is taken by mouth. Common side effects include problems with vision, joint pain, nausea, headaches, and feeling tired. Other side effects include liver problems and allergic reactions. It is not recommended in people with optic neuritis, significant kidney problems, or under the age of five. Use during pregnancy or breastfeeding has not been found to cause harm. In the United States the FDA has raised concerns about eye issues in the baby if used during pregnancy. Ethambutol is believed to work by interfering with the bacteria's metabolism. Ethambutol was discovered in 1961. It is on the World Health Organization's List of Essential Medicines and is available as a generic medication. Chir ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Protein Families
A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be confused with family as it is used in taxonomy. Proteins in a family descend from a common ancestor and typically have similar three-dimensional structures, functions, and significant sequence similarity. The most important of these is sequence similarity (usually amino-acid sequence), since it is the strictest indicator of homology and therefore the clearest indicator of common ancestry. A fairly well developed framework exists for evaluating the significance of similarity between a group of sequences using sequence alignment methods. Proteins that do not share a common ancestor are very unlikely to show statistically significant sequence similarity, making sequence alignment a powerful tool for identifying the members of protein familie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
